Alicyclic diketones such as 2,2-bis(4-oxocyclohexyl)propane are useful compounds as intermediates of materials of medicines, materials of industrial chemicals, materials of polymers, polymerization initiators, heat resistance improvers, antioxidants and the like.
As a process for producing alicyclic diketones, a process comprising oxidizing alicyclic diol to produce alicyclic diketones has be en known for a long time. For example, Japanese Patent Laid-Open Publication No. 59742/1992 describes a process for producing 2,2-bis(4-oxocyclohexyl)propane, which comprises oxidizing 2,2-bis(4-hydroxycyclohexyl)propane by hypochlorous acid and the like in the presence of a solvent.
The process described in Japanese Patent Laid-Open Publication No. 59742/1992, however, has a problem of using expensive alicyclic diol. If 2,2-bis(4-hydroxyphenyl)propane that is relatively inexpensive is used as a starting material, reactions of two steps, namely, hydrogenation reaction of 2,2-bis(4-hydroxyphenyl)propane and oxidation reaction of 2,2-bis(4-hydroxycyclohexyl)propane obtained by the hydrogenation reaction, must be conducted to produce 2,2-bis(4-oxocyclohexyl)propane, so that the process becomes complicated.
Similarly to the alicyclic diketones, alicyclic monoketones (hydroxyphenylcyclohexanone derivatives) such as 4-(4'-hydroxyphenyl)cyclohexanone and 2-(4-oxocyclohexyl)-2-(4-hydroxyphenyl)propane are also useful as intermediates of materials of medicines, materials of industrial chemicals, materials of polymers, polymerization initiators, heat resistance improvers, antioxidants, liquid crystal compounds for display and the like. However, the aforesaid alicyclic diketones such as 2,2-bis(4-oxocyclohexyl)propane are commonly used as the intermediates, and any literature on the technique to produce alicyclic monoketones was not found as far as the present inventor investigated.
Accordingly, there has been desired development of a process for producing alicyclic diketones by which alicyclic diketones such as 2,2-bis(4-oxocyclohexyl)propane can be obtained in high yields through simple steps using inexpensive materials.
There has been also desired development of a process for producing alicyclic monoketones by which alicyclic monoketones such as 4-(4'-hydroxyphenyl)cyclohexanone and 2-(4-oxocyclohexyl)-2-(4-hydroxyphenyl)propane can be obtained in high yields through simple steps using inexpensive materials.
In connection with the above, Japanese Patent Laid-Open Publication No. 134009/1996 describes a process for producing alicyclic diketones such as 2-(4-oxocyclohexyl)-2-(4-hydroxycyclohexyl)propane, which comprises hydrogenating bisphenols such as bisphenol A in a liquid phase in the presence of a palladium type hydrogenation catalyst and an alkali metal compound with heating under pressure.